A native of Egypt, Isidorus, the name by which he is known in almost all sources, was the son of Anthemius, the consul of 405 and grandfather of Emperor Anthemius, making Isidorus the Emperor's maternal uncle. Anthemius Isidorus Theophilus was probably his son.

After serving as praetorian prefect of Illyricum (22 April to 10 October 424),[2] Isodorus himself was appointed to the powerful post of praetorian prefect of the East (29 January 435-4 August 436). He provided supplies to the city of Ephesus during a famine, which thanked him in an inscription; while praetorian prefect, he received two letters from Isidore of Pelusium. In 436 Isidorius was appointed consul prior, along with Senator.